Four members of a Herndon, Va., family found dead in a house damaged by a fire yesterday had all been shot in the upper chest in what police said was a possible murder-suicide.

Although police withheld names while trying to find the next of kin, neighbors said those killed were Richard and Benet Hamilton, and their daughters, first-grader Sara and third-grader Kathryn "Katie."

A neighbor called 911 at 8:13 a.m. to report a fire in the family room behind a two-car attached garage. Firefighters arrived at 8:17 and put out the fire in 15 minutes, said Battalion Chief Leonard S. Murry.

They found four bodies in the house and took three into the front yard and one into back yard, where they were covered and remained until about 5 p.m. while medical examiners and homicide investigators examined them.

"No attempt was made at resuscitation," Chief Murry said, when asked if there was any sign of life.

Mrs. Hamilton's stepson, Evan McLeese, 20, had lived in the house in the 1300 block of Bayshire Lane. He heard the news while on the job at a Target store and came to the home early in the afternoon. After talking to police, he went to stay with friends nearby, Fairfax police spokeswoman Julie Hersey said.

Sgt. Donald Amos of the Herndon police department would not say whether authorities had found a suicide note, or if the family had any difficulties. He said the stepson, who graduated from Herndon High School in 1998, is not considered a suspect in the killings.

The cause of the fire has not been determined, but is suspicious, Pvt. Hersey said.

A fireplace is on the outside end of the family room, which was heavily damaged. Fire had burned a hole in the roof. An upstairs window had been broken by firefighters to allow fumes and heat to escape.

Chief Murry estimated damages at $150,000, explaining that smoke and heat had permeated every room. From the outside, the rest of the two-story brick-fronted, gray-siding house appeared undamaged. A Halloween Dracula was on the front porch.

On Halloween night, Mr. Hamilton was dressed like Dracula, complete with long teeth poking out of his mouth, and Mrs. Hamilton was wearing a mask as they escorted their daughters around the neighborhood, said one neighbor, Rick Taylor, 43.

"They were a very, very loving family," Mr. Taylor said, adding they also had three pet cats.

Mr. Taylor said he saw Mrs. Hamilton every morning when she walked her daughters to the school bus stop, where she kissed them and "would say, 'I love you.' "

Word of the tragedy soon reached Clearview Elementary School. Principal Sheila Bertrand went to the blocked-off street, returned to school, and summoned crisis counselors to meet with students.

"At 9 a.m., no one knew what was going on," said another neighbor, Skip Singer, whose daughter was a friend of the Hamilton girls.

Mrs. Hamilton was employed as research nurse at the National Institutes of Health. Mr. Taylor did not know Mr. Hamilton's occupation. Mr. McLeese is Mrs. Hamilton's son by a previous marriage.

The bodies were found in different rooms of the house, Pvt. Hersey said.

Neighbor Viyaja Raja said she wasn't aware of the fire until she heard firetrucks and saw flames shooting from the back of the garage.

"It's a very sad thing," she said.

The federal Bureau of Alcohol, Tobacco and Firearms also was investigating the blaze, which Fairfax police spokeswoman Amy Lubas said is routine for fires in which there are multiple deaths.

"This is a very, very quiet neighborhood," said Sgt. Amos, explaining that only one other murder has been committed in Herndon this year, and, "I can't recall us having a multiple homicide before."